Millions of public dollars have been spent for the transportation of poor and unaccompanied children, some as young as 3, to rehabilitation clinics in the Rio Grande Valley even though the rides have been illegal for years.

"With no parent on the ride or service, there's little in the way of checks and balances to let the state know if there were problems or if the ride or therapy session even happened," said Stephanie Goodman, spokeswoman for Texas Health and Human Services Commission (HHSC), which oversees both Medicaid and the van service.

Data obtained by the Houston Chronicle shows the Medicaid-paid van service - set up decades ago to ferry low-income children to physical, occupational and speech therapy - as well as Medicaid payments to rehabilitation clinics that directly benefit from the transport service are higher in the Rio Grande Valley than any region in the state.

For the first 10 weeks of this year, 14,455 children made 665,605 one-way trips to clinics in Hidalgo, Willacy and Cameron counties. The rest of the state? Only 6,998 children and 159,081 one-way trips to clinics.

The Office of Inspector General for HHSC confirmed Wednesday it now is investigating why the number of trips and therapy payments in the Valley far outnumber anywhere else in Texas - a state already rife with a thriving health care fraud market.

Statewide, Medicaid-funded transportation for children costs taxpayers $193 million annually.

Of that, more than $50 million goes to the area that includes Hidalgo County's McAllen and $53 million goes to the area that includes Houston in Harris County. But in Hidalgo, annual Medicaid speech therapy payments alone are four times that of Harris County, which has more than two times the number of eligible children.

Medicaid paid $36 million in 2011 for speech therapy for children in Hidalgo County; $9 million in Harris.

"When you have Hidalgo County spending three or four times more than Harris County, which has more children on Medicaid, that's a problem," Goodman said.

Many parents can't go

But one clinic executive says too few parents have driver's licenses in Hidalgo County because they are not legal citizens or are at work, don't own cars, or are not able to attend therapy or ride with their children.

"I would tell you that most of the people do not attend their kids' therapy sessions," said Mario Garza, of The Advocates for Patient Access.

"Typically there is a monitor that rides with the child who has been granted authorization by the parent," said Garza, who is chief operating officer for Dynamic Children Therapy Services in McAllen. "This practice has been in place for over 11 years."

The monitor, Garza said, is a paid staffer of the clinic.

"We think it's clear that state law didn't intend for someone who is employed by the Medicaid provider to serve as the authorized adult," HHSC's Goodman said. "If that's the case, why even have the law?"

Garza claims therapy payments are so high because of the overwhelming number of disabled children, children born with birth defects and children without access to prenatal care - though when asked for specific statistics, he said he had none.

Children riding alone

The Medicaid-provided transportation service and the cost of clinics surfaced two months ago, when state workers repeatedly spotted young children riding alone on the vans.

The state's Medicaid chief, Billy Millwee, on March 15 sent warning letters to the clinics stating that children under the age of 15 could not ride in the vans without an adult.

"Please be reminded of the above requirements and HHSC's intent to enforce compliance," Millwee wrote.

The argument spilled into a Travis County courtroom, where Valley clinic owners are challenging the law. They obtained a temporary restraining order until a hearing can be held on May 17.

HHSC Commissioner Thomas Suehs has claimed the injunction endangers children. The state law was put in place after vans "trolled the streets of Houston," picking up children without parental consent and then billing for therapy that never occurred, he said.

"We will comply with the judge's order but it sets up a framework for fraud and puts children at risk," Suehs said.